We're awash with properties for sale.

That's according to new data released today showing the number of Auckland unsold properties more than double in the past year.

Real Estate Institute data showed 13,861 homes for sale in June last year. But that soared to 25,271 nationwide last month.

Fewer places are selling - due to factors including rising interest rates and high prices.

National house prices rose a median 1.2 per cent from $840,000 in May to $850,000 last month.

And Auckland house prices rose 2.8 per cent from $1,125,000 in May to $1,156,000 in June.

Every region except the West Coast had for-sale property volumes jump 40 per cent or more.

Wellington inventories rose 179 per cent from June to June, Manawatu/Whanganui levels jumped 131.8 per cent, Nelson rose 186 per cent, the Bay of Plenty 158 per cent, Waikato 130 per cent and Otago 101 per cent.

New Zealand sales volumes dropped 38 per cent annually.

Auckland was down 43 per cent, the Bay of Plenty 41 per cent, Gisborne 39 per cent, Wellington 38 per cent, Canterbury 33 per cent and Otago 19 per cent.

It took a median of 44 days to sell a New Zealand residential property, up 13 days on June last year.

Hawke's Bay properties take the longest to sell: a median 66 days, Otago places take 52 days to sell and Manawatu/Whanganui 54 days.

Jen Baird, REINZ chief executive, said: "The figures indicate stock is staying on the market for longer. More stock on the market means more choice for buyers.

"With stock growth in some regions in triple figures, the urgency we saw through 2021 has eased and buyers feel they have more time to find the right property, undertake their due diligence and make an informed life decision," Baird added.

Factors at play included lengthier sales processes as more sales were conditional on finance or sale of a home.

"Further, access to finance and concerns around inflation and rising interest rates cause hesitancy amongst would-be buyers and sellers."

The REINZ house price index rose 0.7 per cent annually. That was down 9.5 per cent from its peak last November.

"Reports from real estate professionals across New Zealand suggest owner occupiers remain strong in the market," REINZ said.

"First home buyers are back, confidence boosted by current dynamics and the Government's May Budget announcement, which increased the cap on the price of property eligible for a first home grant and the removal of caps for first home loans."

But investors were less active than before.

"More negotiation is happening in the market as buyers are more cautious of potential price declines after they have purchased and vendors understandably want the best prices possible in an uncertain market," Baird said.

Presenting places in a particular way or adjusting price expectations to give agents the ability to negotiate were factors now key to selling a place, Baird said.

REINZ expected sales activity to keep falling during the winter months. Baird said that was part of the usual annual property cycle.

Sales activity had been below expectations but the drop wasn't stark, she said.